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Last updated: 02 July 2021
Installing renewable energy sources in your home is a great idea. It can help you reduce energy bills, reduce your carbon footprint and raise the value of your home.
What is energy storage?
Most sources of renewable energy available for your home can only produce electricity at specific times of the day. For solar panels, electricity can only be produced while the sun is up, while most of our energy is consumed in the evenings. In the winter, homes need to use more energy to stay warm but shorter days mean solar panels will produce even less energy.
One way to fix this problem is through home energy storage. Devices like thermal stores, electric batteries and heat batteries can all be used to store any excess energy you produce to be used later in the day when demand is higher.
Types of home energy storage
A variety of home energy storage options are available depending on the type of renewable energy you are using and what you’re using it for.
Thermal storage uses a large, highly insulated water tank to store hot water for hours after heating. Tanks come in a range of sizes from 120L to 500L and can be used to provide hot water for central heating.
Thermal storage tanks can take energy inputs from several different sources including biomass boilers, heat pumps, solar-heated water and solar PV. Excess energy from these sources is diverted to heat the water inside the tank.
Thermal stores might not be able to fill all a home’s entire demand for hot water but will go some way to reducing your heating costs.
Thermal storage units vary in price depending on size and ease of installation. You can expect to pay found £2500 for a 500L unit and an extra £450 for installation.
Heat batteries are a more recent form of energy storage. Heat batteries tend to be smaller than thermal stores and can store energy for longer periods. Heat batteries can also account for a larger portion of your home’s energy needs, giving you a cheaper energy bill.
As a relatively new technology, suppliers of heat batteries are limited. The current list price from Sunamp is £1,300, but this price is likely to drop in the coming years as the market grows.
Electric batteries can store any excess electricity produced by solar PV, turbines, or other generators. These are particularly useful as most electricity is produced in the day, but more is consumed in the evenings.
Batteries come in a range of sizes depending between 4KWh and 20KWh depending on your home’s energy needs.
Electric energy storage can reduce your reliance on the national grid and are popular with ‘off-grid’ builds but can also be effective for anyone looking for a cheaper energy bill and a smaller carbon footprint.
Home-use electric batteries are have seen massive growth in the last few years with companies like Tesla jumping into the market. Currently, batteries cost between £2,000 and £4,000 for a 4KWh battery and up to £15,000 for 20KWh. Prices are expected to drop in the future as the market grows.
Will energy storage save me money?
Feed-in tariff payments
Renewable energy systems have been able to sell excess energy back to the grid through Feed-in tariff (FIT) payments.
In the past, the FIT would pay you a flat rate for 50% of your energy generation, even if you were using home energy storage. Now more houses have ‘smart meters’, payments can now be determined exactly by the amount of energy you put back into the grid. If you are already registered for FIT, this will likely cause a decrease in your payments.
As of March 2019, the FIT scheme is not accepting any new applications, so any newly installed renewable energy sources will benefit from an energy storage unit as you will not be able to sell this energy back to the grid.
Most energy storage systems are relatively new, making it difficult to put any definitive numbers on how much you can save. Savings depend heavily on what kind of renewable energy you are using and whether you are already registered for the Feed-in Tariff scheme.
Grants are available through the Renewable Heat Incentive (RHI) scheme, although it is important to check your home is eligible first.
To find out what kind of savings you can make through home energy storage, compare quotes from several different installers to find out how much you could save on your fuel bill each year. If installing an electric battery, you can find some guidance through the Renewable Energy Consumer Code (RECC) and BRE National Solar Centre (NSC).
Much of the home energy storage technology is still in its early stages and is likely to drop in price over the coming years.